Diffusion of Lanthanum/Cerium/Manganese in Rare‐Earth Heavy Rail Steel at the Refractory Interface

One of the key factors determining the degree of erosion in the outlet parts of refractory interfaces is diffusion. By studying the representative diffusion behavior of lanthanum, cerium, and manganese in molten rare‐earth high‐carbon heavy rail steel using different refractory interfaces, the diffusion kinetics mechanism of each alloying element is illustrated. The results show that the concentration of diffused lanthanum, cerium, and manganese in rare‐earth high‐carbon heavy rail steel imparts minor changes on the two aluminum–magnesium refractories used in our experiments, whereas the other four refractories show unstable behavior. Furthermore, it is revealed that the smaller the porosity of a refractory material, the greater the decrease in the diffusion channel of each element in molten steel, which in turn increases the diffusion activation barrier and results in slower diffusion. Overall, the suitability degree of the refractory materials tested in experiments for processing molten rare‐earth high‐carbon heavy rail steel with regard to cost, adhesion strength, and erosion degree is as follows: Al 2 O 3 –MgO > Al 2 O 3 –MgO–SiO 2 coating > Al 2 O 3 –SiO 2 –SiO 2 coating > Al 2 O 3 –SiO 2 > Al 2 O 3 > ZrO 2 .